Not all of Construct is translatable, but it doesn't seem you translated everything. There's one little problem with charset - it is by default set to "Western". Polish users would prefer "Central European", other languages need other charsets and so on.

Common -> Generally has two meanings: "Wsp�lny" and "Og�lny". I suggest the second.

Every subsequent build from now will feature more translateable areas, as detailed in this thread:

One note: the errors you got are because application, layout and layer properties are not yet meant to be translated. Keep an eye on the thread linked, and hopefully soon they will be, and you can reuse your translations there. For now, keeping to the areas listed will ensure no errors.